These studies are, in part, a sequel to recently completed studies with Streptococcus pyogens and its L-form and includes a pathogenic group B streptococcus and its L-form in comparing and stressing a structure-function relationship between related cellular components and pathogenesis. In so doing, the importance of this relationship and of toxic elaborations relative to the activities of the L-forms of these streptococci in vivo, and in terms of their altered physiology and membrane structure with loss of cell wall formation is given special consideration. The specific aims are: (1) to detail the amount and type(s) of lipoteichoic acid being excreted by S. pyogenes and its physiological L-form and to compare the binding and destructive effect of cellular and extracellular lipoteichoic acid from these organisms on human cells and a kidney organelle (the glomerulus) in tissue culture. Also, to investigate a new approach for the restoration of pathogenically related parameters in this L-form through use of a tissue culture-immunosuppressed animal system and (2) to obtain basic comparative information on the propensity for L-form production by freshly isolated vs a laboratory maintained strain of a group B type III streptococcus and to detail changes in antibiotic sensitivities within these parental cocci before and after reversion from the L-form. Also, to characterize lipoteichoic acid and to quantitate the sialic acid sialidase activity of an L-form from this streptococcus and to relate these findings to its potential pathogenic capabilities in vivo through use of sialic acid-containing host cells in tissue culture.